The sum of all electromagnetic forces between different particles of a system of charged particle is zero

Options

A. only if all the particles are positively charged
B. only if all the particles are negatively charged
C. only if half the particles are positively charged and half are negatively charged
D. irrespective of the signs of the charges.

Answer

To solve the question, we need to analyze the electromagnetic forces between charged particles and understand how they interact according to Newton's third law of motion.

### Step-by-Step Solution:

1. **Understanding Electromagnetic Forces**:
- Electromagnetic forces arise between charged particles. These forces can be attractive or repulsive depending on the nature of the charges (like charges repel, unlike charges attract).

2. **Newton's Third Law of Motion**:
- According to Newton's third law, for every action, there is an equal and opposite reaction. This means that if particle A exerts a force on particle B, then particle B exerts an equal force in the opposite direction on particle A.

3. **Considering All Possible Charge Configurations**:
- The question asks about the sum of all electromagnetic forces in a system of charged particles. We need to consider different configurations:
- All particles positively charged.
- All particles negatively charged.
- Half positively charged and half negatively charged.

4. **Analyzing the Forces**:
- In any configuration, the forces between pairs of particles will always occur in action-reaction pairs. Therefore, for every force exerted by one particle on another, there is a corresponding force that is equal in magnitude and opposite in direction.

5. **Conclusion on the Sum of Forces**:
- Since the forces are equal and opposite, when we sum all the forces acting on the particles in the system, the total or net force will be zero. This holds true irrespective of whether the charges are positive, negative, or a mix of both.

6. **Final Answer**:
- Therefore, the correct option is that the sum of all electromagnetic forces between different particles of a system of charged particles is zero **irrespective of the sign of the charges**.